Today's US-Sold firecrackers only have about 50mg (or less) of pyrotechnic material. Enough to be proven not to break the skin. However, there are many misconceptions about them which cause panic among today's paranoid/underinformed population. M80's and cherry bombs have been extinct since the 60's. Ya just can't buy them.
Still, here are a few fun examples of creative firecrackery, Call it satire, boobs.
1. Use for bird and cat control. They will do no real harm. Just ignite in the vicinity of said pests. Repeat periodically.
2. Toss 'em in the driveway and wait for the old lady across the street to call the Bomb Squad.
3. Drop' em in the old lady across the street's underwear.
4. Light, hold firecracker by the butt end, and impress your friends with your "Super Powers." Use the very tips of your fingers. Hold at arm's length. It might sting a little, but you won't get really hurt. "Sell" the act by pretending to be horribly inured. "Recover" quickly. Repeat.
5. Drop 'em down big-city subway grates. They echo for blocks through the tunnels. Run like hell.
6. Attach a long fuse. Light and drop outside your house. Go in and close the door. Observe how truly lame and not very loud they they really are. A dog bark is generally louder, in effect.
7. Tape to a punk, light, hide assembly in bushes and walk away. This can create a timed fuse of up to 30 minutes.
8. Drop them down Donald Trump's underpants.
9. Keep a box of those tiny little "snap pops" handy whenever playing with firecrackers. Present in case the police show up. Makes any complaintant look like a complete fool.

Tape a whole bunch tougher, wrap them in newspaper, curl the top, light the top, run like theres and firecracker bomb about to explode behind u

Get one and before it explodes, CHUCK IT IN THE LAKE!!!!!!
IT GO BOOM!!!!!!

here are some of my favorite uses:
mold wet sand or clay into a sphere, dry it out, insert a firecracker and you have a sand grenade (or clay shell.)
use the afterforementioned apple grenade trick.
just throw them (this is oddly satisfying.)
tape 7 together in a hexagon pattern, and make a column about 6-7 inches high, and light the top fuses, and you have dynamite.
make dynamite with m-80s (must be lower than 50 grams of pyrotechnic powder in USA) throw it in a garbage can full of water (metal) and watch the geyser.
dig a hole, insert firecrackers and fuse wire, fill it in so the wire sticks above the ground, light it and run.
throw apple grenades.
place strip in metal wastepaper basket (solid walled not holed) and light it, sounds like gunfire.
drill holes in 2x4 and place firecrackers in each one, light them one at a time (i will not tell you what happens.)
throw in lake (not talking about killing fish.)
throw in paint.
throw in fire.
throw in loose soil.
fill pipe up with them, and then drop in a lit one ONLY CAP ONE END, CAPPING BOTH MAY RESULT IN INJURY!
throw in alcohol or gas (not recommended.)
make a firecracker line consisting of more than 50 firecrackers.

if you still have firecrackers left over after all this i envy you.
I AM NOT LIABLE FOR ANYTHING STUPID OR SMART YOU DO!

Here's a description of "guyfrom7up": Take a pop can, cut it in half and use the bottom part. Put a hole just the right size for the fire cracker to fit in and be "inside the can". get a pan of water with about an inch of water in the bottom, and then put the can so the open part is in the water, light the firecracker and watch. The explosion from the firecracker has nowhere to go but propel the can up.

Take a can of soda, drink it, crush it, put a firecracker inside of it, and light the firecracker. It should push the crushed can back out into it's original shape.

String up "a bunch"...

get black cats or m-80s and some gold fish in a tank. light fuse, drop in tank, skimm fish from surface. ooooor find a place w/ lots of sunfish, make a pikilo pete bomb, light, throw, skim, eat.

Shove them into aples, light them, and let the apple blow up all over the place

Stick it in barbies body and blow her up fron the inside

this is never before seen. Take a bamboo pole and tape a bullet shell casing to one end of the gun. then stick in a firecracker and wedge a pebble over the firecracker. light fuse, shoulder and wait!

blow up things with them

stand on them with shoes . don't use bottle rockets they mite slip out from under your shoe.

push them as deep down into an ant hill hole as you can and watch it explode

take them apart, and make huge ones

Oh, and thanks for spamming your youtube.

throw them at people

Take one of those toy parachute toys, strap one to it with a decently long wick, Light it and toss the army man from high up. He'll explode in midair!

You can destroy furniture with as little as one bad boy, we once went overboard and put a homemade high explosive inside one of two identical chests of drawers that were needing destroyed... The bad boy exploded and obliterated the whole thing The high ex. charge left around fifty feet of destruction, there was nothing you could really pick up other than screws...

bury it and light it strap to action man and make a suicide bomber to attack barbie strap to rc car and deploy in fake batttlefeild, put on styrofoam and ignite in middle of pond/lake

i think you can do something with a soda can and putting it in a cup of water... and you do something and it turns into a rocket. I don't know how to do it, but my neighbor does it.

Blow up a juice box.