activities - how to decide?

Recently, I've begun running into one of the problems that face modern parents of multiple offspring: the huge number of activity opportunities and how to decide on which ones to do.

Offspring #1 is interested in art, so I'd like to put him in art class. But we also believe it's important to have a good basic working knowledge of music, so we'd like to have him take piano lessons. He likes tae kwon do, so we'd like him to do that. But his father believes it's important to play a team sport, so he'd like him to do that. In addition, there are things like swimming and skating that are good skills to know, so we'd like him to take classes in those.

And that's just one! Offspring #2 loves to swim, but he also loves to run fast, and might be good at some of the team sports. But those require practices during the week AND games on weekends. He's the dramatic sort, so a beginner acting class might be fun.

Etc., etc., etc. Now, they're only 4 and 5, but the breadth of opportunities gets wider as they get older, and their sister will be coming up behind them with her own set of interests. And while I don't mind if they do some of the basics together (swimming, piano, etc.), I want them each to have their own interests so they're not always competing with each other.

When you come down to it, even if they each only do one activity at a time, that's three items a week (or more, if there are practices/games). And only one person to get them to all these things, so there has to be a limit to what they can each do. (We won't even mention the money this all costs.)

So while I feel that activities outside school are important, I have neither the time or money to go overboard. Which leaves me feeling the need for some kind of a metric scale to determine how, exactly, to narrow it all down so that I feel like they're getting a broad range of experiences without driving myself crazy.

Perhaps in practice, as they get older, they'll make these decisions on their own and it won't be as hard as I anticipate. I can always hope.