Like most of you I often play casual rounds with the same group of guys and we've developed a way to raise decent chunks of cash to sponsor holes and such.
Before every round each of us declares our own personal par for that round. At Dexter, for example, I go with even. Someone else might be +1 or +4 or whatever. Your choice.
If you shoot your own par or better, you owe nothing. If you shoot worse you owe a buck. (Sometimes I've shot worse than worse and I'll kick in $2.)
You can play skins too, but I suggest just using the skins to keep score. So whoever wins the most skins pays nothing. 2nd and 3rd place owe a buck, 4th place owes $2.
We keep a log with the total amount each person owes, and it adds up pretty fast. Then we vote on how to spend it. For each dollar you owe, you get a vote.
We probably raise $400-$500 a year and it's pretty painless. A lot easier than knocking on doors begging for cash. It's just an easy way to raise money, and if lots of people did this our tournaments and clubs would have lots of money!