I know, I know. I left it too late to design a new model for Valentine's day. Please accept my most humble apologies! I'm in the process of making a Valentine Robot which I'll probably release anyway, as an incredibly early model for Valentine's Day 2011.
Meanwhile, I've uploaded a model, originally available on the flying-pig.co.uk website. The Fluttering Heart folds flat and slips inside a book or card. When the card is opened the heart pops out releasing a 'flutter' of heart strings!
I hope your true love enjoys it as much as mine did 🙂