There are several places on the board where you can participate.
http://www.quiltingboard.com/quiltin...-contests-f21/
http://www.quiltingboard.com/member-...ow-robins-f11/
http://www.quiltingboard.com/blocks-month-week-f9/
There's not an easy way to be notified of new events, so you just need to check back every so often to see if something new has been added. The only ones I know of that are 'closed' events are where there is a swap. The host needs to pair folks up and/or know the number of participants to make the swap. You need to sign up by replying to the thread before it's full. The other events, like challenges & block of the month/week, you can just jump on the wagon at any time by posting to the thread.