I've done it in several adventurous places
In various cars, one time inside a miata(that was kinda tough to work out)
On a crowded tour bus(hands only)
In various parks, outside of the car in soccer field parking lots at night
Downstairs of my current gf's house, with parents home and her sister awake
And the latest risky adventure I've had:
My current gf and I had sex in an outdoor shower stall at the Virginia International Raceway last weekend. That was tons of fun