Microsoft Research has recently started selling some of its research software as real products. One of the first was AutoCollage that was developed by guys here in MSR Cambridge. This is a very nice tool - I have a collage of the girls on my office wall generated by the beta version.
The latest product is SongSmith. This is a very cute app that automatically generates musical accompaniment to a vocal line (supplied by you!). The demo video is very neat. The girls would love this!
Both are available at credit-crunch-prices (TM): $19 for AutoCollage and $29 for SongSmith (although the website wouldn't let me buy SongSmith five minutes ago - probably still being updated...).