At 10 and almost 12 my two have (I'm pretty sure) managed 49 of the 50 activities listed: they haven't, to my knowledge, set up a snail race (although they've certainly collected a few). I will now put the thought in their heads.
Climbing trees, rope swings etc is very much part of their daily life. In fact they found their first geocache by accident while climbing a tree to improve a rope swing
I didn't even know what it was then but when they discribed it my husband told us about geocache.
I think it's a bit too easy to blame technology for keeping kids indoors: my two have an Xbox, Ipod touch, DS and access to computers and TV's; they use them all but are more than happy to be out when the weather's right.