So I've been involved with the Ripple monetary project as I've shared elsewhere on these forums, and in the process I've set up a Ripple credit server. A potential application I think could be useful and which may appeal to you would be to use this or another open credit server to run and teach family-related finance. For instance, you could set up small credit relationships to track activities like chores, homework, playtime, and so on. This would let you offload your mental or manual tracking into a nice software package, while providing lots of opportunities to learn together about finance, computers, and other areas.
You can freely use the credit server here:
Please note that you may need to accept a certificate for your browser to recognize it, as I use CA Cert rather than one of the older centralized issuers.
I hope you find something valuable, and would welcome all feedback!