I can't join sketchheroes.com

I found the site from DrawingNow. I found it's similar to DrawingNow but have different modules. It's also an all age website... Even I heard you can join even if you're under 13 (and I'm under 13 but I'm almost 13 on March). I tried signing up three times, cleared my cache a million times already, and then after joining, the page appears blank. I was even refreshing the page and then nothing happened. I didn't even received a site notification e-mail. So it won't let me join. Any helps?