Running a LED on 6v?

[Chriszuma]

I know this isn't exactly related to FIRST, but I don't know of any other place to get the opinion of hundreds of electrical engineers.
I'm going to mod my calculator, and light up the screen with a blue LED and some fiber optic cables. I can get the fibers from a cheapo Ikea lamp of something, but I'm having trouble finding a suitable led; the calc runs off 4 AAAs (6v, in case you're anti-multiplication). I really don't want to pay $3.29 for Radioshaft's 6v-max-rated led, but I can't seem to find any other 6v ones (and i'm beginning to suspect that they are liars). What would you suggest? Possibly only wiring it to 3 of the batteries somehow, or putting a voltage regulator on there? Maybe wiring two leds in parallel (I'm en electronics newb, if you can't tell).

Thanks for your help.
~Chris Hammond