John the Monkey said:Portable workstand?
Laying the bicycle on its side?
Getting a new wheel from the team car?
None of those
For a puncture, I take the wheel out and lean the bike against a hedge or whatever is nearby, obviously taking care not to rest the rear derailleur in a puddle or something. Then I work on the puncture and put the wheel back in when I'm finished. On balance, less risk of damaging the bike than by upending (brake hoods, cables, computers, seat are all in the firing line for damage/dirt when you upend)