Every parent knows that kids are messy little money pits. Luckily, they're so dang cute otherwise we might send 'em back like those boots that looked better in the catalogue. Anyway, since there's no way around most kid-related expenses, like doctor co-pays and new sneakers, it's nice to attend as many free social activities as possible.

Here are a bunch of ideas for free places to take your youngster -- and we recognize older kids might think these events are lame. Please use the talkback feature to tell parents about other local, kid-friendly events that are free, or cost very little.

Watch the roasters at Alterra. The Alterra on Prospect Avenue, 2211 N. Prospect Ave., is always a fun place to observe -- and best of all, it allows mom and dad to caffeine up at the same time. With big machines, a pulley system that delivers bags of coffee to the side register and lots of energetic workers, Alterra's a guaranteed hit with the short peeps.

Ride the bus. Most kids love all forms of transportation, so a bus ride -- on a real, live city bus -- would knock their little socks off. The adult fare -- which includes anyone 12 or older -- is $1.75, and kids under are free. (Kids 6-11 are $.85.) Here's an idea: Hop on a bus heading for Downtown, and walk around the Shops of Grand Avenue. Riding in an elevator and/or escalator is serious entertainment for a toddler or preschooler.

Visit the library. The library is a great place to burn a couple of hours. Younger kids might prefer the Shorewood Library, because it has a train table. Also, you can reserve items online (see the link below), and pick them up at any library, including the Downtown branch that has a drive-through. Of course the only down side to the library is that it's one more thing to put on the to-do list: "return library books." However, the library system naturally teaches the concept of sharing, trust and the importance of reading.

Swing by a "story hour." The Downtown Library has free story time every Saturday at 10:30 a.m. and the East Side Schwartz Bookshop, 2559 N. Downer Ave., has one as well, and it's also at 10:30 a.m.

Check out the Public Museum, Domes and Art Museum, which are free on Mondays (Public Museum and Domes) and Wednesdays (Art Museum) for Milwaukee residents. The zoo is occasionally free, too. If you haven't already, sign up for The OMC Family Weekend Roundup to find out when the free zoo days are happening.

Go to a park. Kids love to swing and slide at the park, but you can take it up a notch by having a picnic, pointing out flowers or collecting bugs. And once the weather really warms up, don't forget about the beach. Atwater Beach in Shorewood is lovely, and has lots of relatively clean sand for building, running and Frisbee tossing.

Slink into the Urban Ecology Center. Visit the Urban Ecology Center, 1500 E. Park Pl., on weekends and do hands-on science experiments or nature-oriented crafts. On Saturdays at 1 p.m., families are welcome to help feed the animals during the center's free Animal Feeding Time. Log onto the Urban Ecology Web site for lots of free family entertainment (but keep in mind that donations are always accepted).