¶ It’s not too late to travel in time.

This one is more for beginners. Basically dress in period clothing (preferably Victorian era) and stagger around amazed at everything. Since the culture’s set in place already, you have more of a template to work off of. (Via Glenn Reynolds.)

¶ Time travel of a different kind: An American soldier in Iraq visits Ur of the Chaldees.

¶ I am a sucker for this kind of thing. For more futures that never happened and dead ends on the road to Now, try Modern Mechanix.