Want to have a cool spikey background? Well, with this tutorial you can learn just how to do one using nothing but PS and your talented wits!
Open a new file - somewhere around 500x500 should do, it depends on what size you want your spikes to be.
Now, press SHIFT+CTRL+N to create a new layer and click ok - Make sure to remember doing this on every start of spikes, otherwise it wont work!
Choose the Polygonal Lasso Tool (second from the top on the left, if something else is selected right click and choose it, it should be there along with Lasso Tool and Magnetic Lasso Tool).
Next, click around the top left corner of your image to create an empty shape of something that looks like the sun rays of a small childs painting. Next choose a color you'd like and fill it in, it should look something like the picture below.
Copy your current layer and paste it over it, then go to Layer > Layer Style > Blending Options and under the General Blending tab (should be the highest one) fiddle with the opacity numbers (anywhere between 0-100) to get a somewhat different color than the one your previous later had.
Repeat all steps between copying a new layer to changing the opacity, until you think you got the right image and like the results. The ending product should look something like this... (Only of course in your colors and shape).
And Viola, you got yourself some cool new spikes!