Bingowings said:

I'm sure you can easily understand a game like Magic but why don't you pretend to be a little bit more green?

Ask if one of them can explain the basics to you and maybe the whole group will get involved. People tend to enjoy explaining their interests to other people.

Just stop being so self conscious matey.

The worst thing that can happen is they can say no in which case just join in with someone else's thing you wouldn't want to hang around rude cliquey people anyway.

Yes, yes. To Drax you listen. Don't overthink shit, just put yourself in a situation and deal with it. You're making it seem much harder than it is.

Just go up, ask what they're playing, say "Oh hey I've always wanted to get into that!" and go from there.