Similar in some ways to Ypnypn's suggestion, the "Shtieblach" minyan factory in Beis Yisrael has a machine in every shtiebl that takes money to pay for the air conditioning. If no one pays, or if the money runs out, the AC turns off. The cost is 2 NIS (~50 cents) per quarter hour. I'm reasonably certain that those funds are used to help defray the costs of the AC ;)

It's been a while, but I'm pretty sure this has been implemented in some shuls in Lakewood as well (though with American currency ;). If I'm not mistaken, the machine I saw in Lakewood controls the lights also (I believe I had the lights turn off on me in the middle of a prayer, until someone paid up), so it's not really as optional as the machine in Beis Yisrael, which means that they're pretty much guaranteed donations from every minyan. This also means that if people are in the shul between prayers to learn, that the lights and AC will be off if not in use.

Similar in some ways to Ypnypn's suggestion, the "Shtieblach" minyan factory in Beis Yisrael has a machine in every shtiebl that takes money to pay for the air conditioning. If no one pays, or if the money runs out, the AC turns off. The cost is 2 NIS (~50 cents) per quarter hour. I'm reasonably certain that those funds are used to help defray the costs of the AC ;)

It's been a while, but I'm pretty sure this has been implemented in some shuls in Lakewood as well (though with American currency ;). If I'm not mistaken, the machine I saw in Lakewood controls the lights also (I believe I had the lights turn off on me in the middle of a prayer, until someone paid up), so it's not really as optional as the machine in Beis Yisrael, which means that they're pretty much guaranteed donations from every minyan. This also means that if people are in the shul between prayers to learn, that the lights and AC will be off if not in use.