This is a cool project I did awhile back. Great for the backyard or bring it to a tailgate.
No gluing - easy to make (about two hours) and setup each year (about 15 minutes)
I bring it out every football season. You can store it in a trash bag.
You only need a hacksaw (I actually used my power miter/chop saw) and a rubber mallet.
Get some 2" PVC. Always buy more than you need. It is much easier to return some than to wish you bought enough.
You need 12 "T" connectors, too.
Step 1: Cut and Assemble
I cut my 10 foot PVC pipes into these lengths:
6 - 32" pieces for crossbars
4 - 12" for short vertical bars
2 - 48" for top vertical bars (with flags)
2 - 52" (or longer if you want) for bottom vertical bars
6 - 32" for feet
2 - PVC caps
Look at the picture. Lay it out on a patio or flat surface for sure - don't do it in the grass.
Each time you attach a piece to a T connector, hammer it in with the rubber mallet (put your foot on the T while you do it or have someone put their foot on while you hammer). Leave the feet for later.
For stability, if you want, grab two or more pieces of conduit (steel electrician's pipe) to slide into the PVC bottom vertical bars for strength.
Step 2: A View of Connections
Looking back, I wish I cleaned the PVC first with PVC cleaner. Too late now, the cleaner doesn't work years later.
Step 3: Add Flags If You Want
These were cut with a scissors from flag football flags. Or get some stretchy vinyl from a physical therapist, which have them on a roll to easily cut.
Put the flags on the top of the top vertical bars and hammer in the caps.
Step 4: Attach Feet
Have someone hold the goalposts while you attach the feet.
I cut a little nub to attach to a T connector to have a foot go sideways so it is less likely to fall down.
Step 5: Done
Pretty easy. Make sure you don't glue it! This way you can take it down and bring it to the tailgate.