How can I get a background like this?

Wondering how I can make a stripy pattern like that for the background.

 

Its a black background?
If you mean on the MLG sign, its a scan line, make a 5x5 canvas, use the pencil to make a diagonal line, and save it as a pattern preset.

 

http://www.createblog.com/photoshop-tutorials/905-diagonal-scanlines.fixed./

A decent tutorial. Scanlines are pretty easy to create, it's just a matter of making the pattern (easy) and defining it as a pattern (very easy)

 

Thanks both of you Exactly what I was looking for.