If Dave Kapell, the creator of Magnetic Poetry, ever needs a pro testimonial, I'm his girl. I've been a magnetic poetry junkie ever since the original kit hit the market back in the nineties, using it to play with words, recharge my batteries, work on titles (you would not believe how many of my novel titles were born on my fridge) and otherwise just have fun.
My favorite kit is contained in The Magnetic Poetry Book of Poetry, which comes with a pouch of magnetic words to stick to the metal-lined inside cover of the book, making the fridge unnecessary (over there on the left is a pic of my latest poem-in-progress.)
Aside from the fun factor, using magnetic poetry can be very helpful to and inspirational for people who for whatever reason can't write. Those attractive little words and fragments can break through enormous writing blocks, refresh a tired soul, and bring back a sense of fun to word- and world-building. I often buy kits for teenagers who have problems warming up to poetry, then sit back and watch them play. Those of us who are physically disabled also appreciate the kits; it brings back the fun of spontaneous creation (and gives my voice a rest.) Sometimes I take my book to PT and pass it around the waiting room, and the other patients all seem to instantly fall in love with it. It's the ultimate in ice-breakers.
I didn't know it until I went link-hunting tonight, but Magnetic Poetry has a massive web site with themed sets, kits, and new products for the creative players of all ages. You can try out some of the kits by playing with them online here if you'd like a preview. I did a little early Christmas shopping there tonight, and I think any of the kits make great and reasonably-priced gifts for kids, poets, writers, or anyone who owns a fridge.
Language is a Virus.com has several online author-themed versions of magnetic poetry you can play with here; my favorite (naturally) is the e.e. cummings version.