Laser would be cool - probably good for outdoor use too.
Can get a really inexpensive battery powered LED/flashlight as a source:
http://www.mpja.com/Flashlight-8-White-LEDs-with-LASER-Pointer/productinfo/17475%20TL/
I bought 3 or 4 on sale for $1 each - one was missing a battery spring so it doesn't work.
Nice metal case, very sturdy feeling. Handy belt-case too. Don't know how long the included batteries will last.