This is a quick and semi painless (driving into concrete can make your arm tired) half day project that creates a sturdy modern looking spot for your boxes of stuff.

Supplies

5 - Straight 8' 2x4's

1 - Sheet of 1/4" Plywood

1 - Box of 1/4" hex head 3" Tapcons

1 - Box 2-1/2" Torx head screws (Phillips can be used if desperate)

1 - Table saw (optional) if no table saw, obtain 10 2x2's

1 - Circular saw

a lot - Masonry bits (if you intend to mount into concrete)

1 - Hammer Drill (a normal drill will work it will just take forever)

Step 1: Rip Some 2x4's

2x4's are far cheaper than 2x2's. So why not buy a few and run them through a table saw. The people above you will adore the sound.

Almost all table saw injuries are avoidable if you use the proper ripping techniques.

Adjust the blade height so the bottom of the blade gullet is even with the top of the wood you're ripping.
Set the fence to the mid point of the 2x4 (2x4's used to be 2" x 4", if you remember having a 2x4 that size then you're probably pretty old, the 4 in the 2x4 is actually 3-1/2") Also factor in the kerf of your table saw blade. if your table saw blade is 1/8" then set the piece of wood at 1-11/16" or 1.6875" or eyeball the middle. this will be the halfway point allowing the 1/8th inch of material to be removed for the split and making the wood equal on both sides
ensure your piece of wood is straight. you do not want to rip wood with the various attributes shown in the picture. this will cause headaches and make your shelving sub-par. (yeah that's good in golf, but not here)
keep the 2x4 against the fence and with a push tool, guide the wood through the saw blades to give you a 2x4 that's now a 1-1/2" x 1-11/16" piece of wood.

Step 2: Frame It Up

Now that you have your ripped wood, it's time to frame the shelving to the wall. This can be done various ways. The method executed for this project was far from the standard way to frame. It did work though.

start lining up the back pieces that will attached to the wall. (note the order from the picture. that is the order that was used here. but doesn't have to be followed exactly) place a level and mark a line to determine where you want the pieces mounted then take a step back and determine if the layout is suitable for your taste.
From the picture if you start at one, cut the piece to length and either hold the piece yourself or have someone hold it up for you then drill some pilot holes in the wood, where the screws will be fastened, in to the concrete just so to the point where you see the mark that the bit made.
take the masonry bit from the package of tapcons and use it to drill the holes into the concrete. ensure the hole is deep enough so that the length of the screw will be firmly against the wood securing it to the wall.
After completing the first piece continue on until the pieces that secure against the wall are attached
Frame the pieces that protrude out from the wall with the torx head screws (yes you can use phillips but they aren't the preferred choice for people who like torx head screws more) ensure each piece is cut to length by measuring twice. the pieces that butt out from he wall here are 12"

Cut List:

1 - 48"
2 - 9"
3 - 10.5"
4 - 46.5"
5 - 48"
6 - 9"
7 - 48"
8 - 48"
9 - 10.5"
10 - whatever was left over

Step 3: Attach the Plywood

Now that you have the frame up, it's time to add the final piece.

cut the sheet of plywood in half vertically then cut each of those in half vertically so you have 4 8 x 1 ft strips
Cut one of these strips in half. you have two of part of the shelves by doing this. now cut another one in half.
- this will give you 4 48" pieces. you only need 3 of these pieces so cut the one 48inch piece into 1/3rds. these will be the sides of the shelving
now measure the remaining gaps and cut to length
Adhere all of the pieces with 1-1/4" screws. be liberal with the amount of screws you use.

If everything is done correctly, you can hold a lot of weight on the shelves. if you take a look at the picture with stuff on the shelves, there's a 50 lbs weight just sitting there asking for more. Now It's time to jump up and down because you're finished, but don't hit your head on the ceiling because that would hurt.