My wife and I were at some store and we saw something similar to this and we thought it would be pretty cool to build one ourselves. We made ours with 7 frames so we could spell out WELCOME but if that's too cheesy for you, you could do NSOP or FTW, maybe IDP. As with any art project, put your own twist on it.

I just got it done and we haven't had time to get photos to fill the frames so I stole some from the interwebs just for demonstration purposes. They will be replaced as we take our own photos.

Materials used:
1"x3"x4' board, pine from Lowes - $4
primer and flat black paint - $2? (I had it)
Frame hangers from Lowes - $1.50
Cheap frames - about $1 each
Total: Around $15

I took the easy way out because I live in an apt. and don't have tools available to get fancy. So I just measured so I'd have 1" in between the frames and I cut the board to length. Then I drilled holes to attach the frames. Sanded the board and painted it flat black. Then I nailed on the hangers and attached the frames and I was done.

Mad tyte shelf building skillz and some of these could also yield similar results