but 3.5b will have something shaderspawn has begged for since uh... a long time. He had always wanted a set of conditional relays so that he could create entities that only work when certain game-related circumstances existed.
Conditional relays are pretty powerful and will allow you to do some pretty amazing things... I'll list a few below to get your mind cranking... you can do an amazing number of things using these if you think them through.
Examples:
Packs that spawn in a flagroom only when the other team is winning.
A Teleporter that works only when the redflag is being carried by a player.
A wall that only exists when teams are tied.
A powerup that is given to every player as they spawn only during over-time.
An elevator that only works when the blue flag is still on the flag stand.
Alarms and sirens that flash and make noise and blink only when the red flag is on the ground, or carried by a player (IE not on the flag stand.)
Those are just some of the examples but I'm sure your creative minds can think of more. You can expect more details from Shaderspawn once he gets the ent def updated to his satisfaction.