There's my Grounhog Card Challenge of course. http://scraphappypapercrafter.blogspot.com/p/random-crafts-of-kindness-contests.html
Card Positioning Systems is celebrating their 5-year anniversary and will be doing card challenges every day for 15 days. I'm pretty excited about this because I love their challenges. I actually feel challenged to follow along and do a card a day the whole time. I think that this will be SO much fun. I'm looking forward to it.
Paper Playtime is doing an "anything goes" challenge and blog hop, which is always a lot of fun.
Jelly Park Challenges has a fun digi Winter Wonderland themed challenge.
The Scrapbooking Queen has her monthly challenge and it is also a Valentine digi theme.
Fantabulous Cricut is doing a 3x3 Valentine card challenge. The sizing is a nice change up from other challenges this month. http://fantabulouscricut.blogspot.com/
Exploring Cricut has a fun 1,2,3 challenge this week that I'm looking forward to doing. You do 1 ribbon, 2 Cricut cuts, and 3 jewels, brads, or buttons on your project. This is a cute and fun challenge to stick to.