It's probably too late for you to sign up for the walk this weekend, though it's definitely not too early to start training for next year. And it's always time to send... money, money, money! If you want to donate to a specific walker, you can look them up there (or shoot SFist a note and we'll introduce you to our super-cool friends!). Don't let not having friends (walking, we're not implying anything) stop you.