Wow! That's a really interesting question - and quite a tricky one to answer.
Personally, I guess there's two ways I'd go about seeking a sense of purpose and joy this week:
Create tasks to complete
A couple of weeks ago I decided that I'd started spending too much time wishing my day-to-day life was different, and probably not doing enough about it.
Rather than make one big sweeping change (something I'm always tempted to do), I've decided to create little "challenges" or tasks for myself to accomplish during the week.
The idea is that, if I manage to pass these little tests, not only will that give me a sense of achievement, but as a sum of all these minor changes, I'll have made a big difference to my life.
The specific challenges don't need to be really difficult or ground-breaking. They can be as simple as "spend more time with my daughter" or "learn how to add an image slider to the website I'm working on using jQuery" - but they're all the kind of things that, if I didn't commit to doing, could easily be put off or forgotten about.
Trying new things
Another rather broad piece of advice, I know, but this is something I'm really hoping to do more of.
I'm guilty of getting comfortable with routine far too easily - so I'm trying to force myself into doing things I wouldn't normally do.
For example, yesterday - rather than spending my free time online, watching football or having a few drinks, I went to a museum and an art exhibit.
Whilst that's certainly no act of revolution, just spending a few hours looking at weird art, taxidermy, and Ancient Egyptian relics was far more inspiring and positive than spending the time on Facebook or going to the pub.
If I can replicate this behaviour on a weekly basis, I think this will have an overall progressive and positive affect on my frame of mind.