Can you point Lightroom and Aperture at the same RAW files?

The answer as ever is - it depends. Both LR and Aperture can 'reference' files in the directory structure of your hard drive, and use their own databases (LR = Catalogue) to store their own application specific data.

Alternately you can set up both to store the original file in their own database, in which case it is much harder.

So, if you want to play with both, I would suggest using the referenced route, i.e. set up a folder structure and set both products to:
Aperture - Store Files in their Current Location on import and
LR - Add Photo's to Catalogue without moving option

This way the originals will remain in the folder, both app's can access them

Cheers

Andy

Note that Aperture won't pick up any edits you've done in Lightroom though. (nor, in the reverse case, would Lightroom pick up Aperture's edits).

Also just be aware that Aperture works significantly differently than Lightroom. So if you really want to see what Aperture can do, you need to give it a decent amount of time. When I tried Lightroom, I thought its tools seemed very familiar to Photoshop's - so there wasn't much of a learning curve. Aperture takes some getting used to. I prefer it; but some people seem to spend 5 minutes, see that it doesn't work the way they are used to and then drop it.