-
But still, I rated not that good, since it's not clear to me what I should do here.
I'd immediately go into browsing the Highlights, they stand out the most. Is that what you want to reach? If not, you might want to consider emphasizing the important parts to the visitor.
Oh, and indeed, there's no 'sign up button' ';)

I'm thinking that the emphasis should be on upcoming events, with highlights as a close second. Basically if they aren't interested in upcoming events, show them how good the past events are to suck them in. I do see that the emphasis should be more clear though, just not sure how yet while keeping the design minimal. I'll keep working at it.