[ig1]

Facebook are well known for their application puzzles,

http://www.facebook.com/careers/puzzles.php

And Google are notorious for having a long drawn out interviewing process.

[jchonphoenix]

Facebook's interview puzzles aren't a prerequisite requirement to getting a job. The good developers who don't have time will just interview and get offers.

Google's are drawn out, but each interview takes 1 hour max so there is an upper bound on your time.