You know, that would be a good idea to have! I'll ask Carol aout it.
The first Telephone challenge has an explanation:
http://www.mousescrappers.com/forums...ead.php?t=3832
The weekly challenge always changes depending on the host.
For the template challenge, the host posts a template that you use, but you can modify it if you like. This challenge doesn't have any prizes, since you are getting a free template.
Here's the Speed Scrap thread with explanation:
http://www.mousescrappers.com/forums...ead.php?t=4848
Kit challenge, the host provides a free kit, and your layout must be 90% using their kit. Obviously no prize for this either, since you are getting a free kit.
The scavenger hunt you can find the explanation in the first thread
http://www.mousescrappers.com/forums...ead.php?t=5392
Scraplift challenge you lift the layout or a layout from the gallery the host posts.
The photoswap has a sticky thread:
http://www.mousescrappers.com/forums...ead.php?t=4591
Think that's all of them!