a guy who has and knows how to use a slim-jim! Or an extra set of keys... kept somewhere outside of the car! Call a towing service. I've known quite a few tow truck drivers who've known what to do in just such a situation.
The most common way is to get an old metal coat hanger, cut it so it is straight then squeeze it in at the top of the window between the top of the window and the door, then use the hook to open the door from the inside. I have done it several times for keys left inside the car...
umm last resort just call the towing people. they might charge hella though. try to smoke the guy out when he asks for money
Find the skinniest, stiffiest stick you can find. Coat hangers work but it's easier with something thicker that won't bend. Use a knife or something to pry the window open as much as you can, and stick your tool down. Use it to unlock the door. It's not easy but that's why I keep a spare key with me all the time now
call tripple AAA they might charge ya and tip the guy a lot. the slim jim wont work if he has a car that's windows go up beyond the window line (nissan Z, pt cruiser, bmw 8 series, etc.) you got an extra pair? call a person to bring em
locksmith that does house calls and other outdoor work. you have some sort of insurence card or other such crap in the car or better yet on you? you'll probably need to prove you own the car before he'll leave if he's going by the book
Note to everyone: put a spare key in the sole of your shoe u wont ever notice it .. under the gel pad in the heel! GL w/ that bro !
I wondered how long it would take someone to come up with that solution! Good one, though somewhat costly...!