Something like this, which can also string together what I do across phone, tablet and computer would be even more interesting.
I was just thinking the same thing - potentially you could mashup Selfspy with our SnowPlow (https://github.com/snowplow/snowplow) project - so all your behaviour events get logged to S3 and then analysed...
as part of my dissertation work, i built a related self-monitoring tool, except with a focus on helping scientists/researchers record and annotate their workflow:
http://pgbovine.net/burrito.html