From my understanding, a danisen is a sort of ranking system. The way it works is that you're put into groups of like 4-6. A match starts and the person that wins keeps going till they lose or get enough points to go up to the next ranking.
And I'll start bringing a set-up with me once a month on a yet to be determined Sunday starting November from when they open till 5 PM. Promise!
Oh God, I'm terrified of spiders, but Daddy Long Legs are really harmless. Get a container of some sort and take it outside and let it go, then get rid of the web.
The official website has a flash game tutorial that teaches how to play, and the old GBC game would give you an idea, but some of the rules are different now.