Things to increase the effectiveness of LEDs?

I'm a college student and this year some buddies and I just got an off campus house. We've thrown a few parties and I'm looking for that extra touch for our basement.

I got about 40 leds of a few different colors and hooked them up to the subwoofer output of our stereo system (I used resistors so they don't get blown). Everything is setup and it works good but the light of the leds is very concentrated. Is there anything cheap I can use to disperse the light on the wall into a cool effect or just a wider spread?

Maybe something that is used in flashlights to adjust the width of the light?
Suggestions should be practical and cheap!!

Get a finegrit paper (300) and sand the front of the LEDs.

I would assume you are using 5mm LEDs instead of high powered ones so the sandpaper trick will probably work just fine.

You could also try to use pieces of a T8 fluorescent diffuser if you want to try a different effect. Usually you can find these diffusers always getting broken and thrown away. Or you can "aquire" some from the college.

The dome of the LED concentrates the light. Cutting it off so the top is flat spreads the light out.

ARCmania discovered this a long time ago and used this trick in the MJLED/SMJLED series of LEDs.

cut a 1-2inch piece of plastic straw and put led into the straw.even better effect would be if straws have colored stripes.

Take some old wire cutters and just cut the dome part off of the LED. Easy as cake.