The following are some ideas from Pepper, one of the co-founders of PSD, in response to folks asking how to do it on their own (and without our system):

You can run a speed-dating-like event using a “table for four” structure, where people meet more than one person at a time.  This tends to handle mixed sexualities better because you just meet more people.  The format goes like this:

1)  At the beginning of the event, give everyone a nametag with a unique name on it.

2)  Also at the beginning, have each person pick colored paper with numbers on it out of a number of buckets – one bucket for each color.

3)  The event consists of a series of rounds, where you call out “go to the table with the number on the red piece of paper” and then people go there.

4)  Due to the way you set up the numbers in the buckets, each table has 4 people.

5)  In the round, people introduce themselves and talk, maybe for 10 minutes or a little longer.

6)  After the time, end the round and have people get up and mingle.  If they liked someone, they write their nametag name down on a sheet of paper.  They can also just write down folks they meet while mingling.

7)  Start a new round after a little mingling.

8)  At the end, collect the sheets of paper.  Order them alphabetically and manually cross-check them.  If two people wrote down each others’ name, send them email with each others’ email or (if at a campout) introduce them.

If you have too many rounds for colors, you can put a round number on the paper instead of having a color.  Though really, you should probably stick to no more than 8 rounds with lots of mingling – the mingling is where the magic actually happens.  You’ll need to meter the number of tables that go into the buckets by the number of people who show up, though if a few tables end up with 3 people that’s okay.

This can be run pretty easily with some prep, including at a campout or burning-man-style event.  Save enough time for the cross-check at the end and get a number of people working on it – it can be a lot of work.  Maybe do a practice cross-check run to see how it goes.

Pay attention to event atmosphere as well.  You want to make it feel like a romantic dating event, not like a church prayer meeting with bright lights and uncomfortable chairs.  Consider whether to have alcohol or not – it can go either way.  Make it easy to socialize before, during, and after the event.  The real trick of these events is getting a bunch of people in a room together, all of whom are looking for new partners.

There’s no actual minimum size, but if you have fewer than 20 people it could get a little weird, I would expect.