Well, profit events are basically events where your earnings are larger that the expenses.
For eg, Hecktor's "500 event".
500 members had to join at the price of 500tc,
Then he bought a void force out of the entry money. Now, the void costed less than all the money he got so 500x500=250000.
250000-void force=profits of remainder.
I guess that was a bad example because it was like a raffle.
Another eg,
Have a Tourney with an entry fee, have the prizes be worth less than all the combined entry fees and then all you need to do is host.
Hope you can understand that.