If anybody is bored enough, take a good long read through this part of the report that discusses the possible failure sequence of WTC7. Some out there will simply say "pah, government sponsored crap!" but personally I think its the best feasible explanation I've seen anywhere. No conspiracy theories, just plain old laws of physics on a complex structure only 350 ft away from one of the biggest building collapses that has ever occured.
http://wtc.nist.gov/progress_report_.../appendixl.pdf