Splat Zone. I like this field better than splat zone because it is outdoors and easy to get pinned down in. Flags and Wheels is indoors and is fun to play in.
This is a good place to hone your room to room attack techniques. You can use your own gun, as long as you can lower the velocity below 200 fps. If not, you must cut the spring or use a field rental. The field rentals aren't too great, they have been abused greatly and the actions are very worn and subject to failure. Their masks are scary to use. I don't know how well they clean them. You must use their expensive paint ($6/100rounds!!!!) Overall, a good place to play once-in-a-while.