Hill Climbing -- A More General Question On Systematic SQL Skill Upgrade

I'm wondering if someone has thought about this, one desires to enhance
his/her sql skills proactively vs. skills gained over a period of time
merely because of work experience. SQL skill here refers to mainly MS
SQL Server related skill.

What could be reasonably effective ways to go for the proactive
approach?

Off head, I'm thinking of the following:
*) read up and re-read on a few selected books such as sql for smartie
except old textbooks (some of them have been read/studied)?
Little challenge: definition of great sql books or online materials?

*) get into a habit of visiting some good sql web sites include MS sql
web site. Little challenge: definition of "good sql web sites"?

*) form a routine of reading good SQL NGs like this
Little challenge: which thread(s) to read? By interest only is sort of
limiting.

*) find an interesting project (non-work related) to embark on to test,
verify the above three?

Big challenge: the above 1 through 3 is pretty dry, how could one
manage to do it in the evening/at night after work when a bit tired and
desires to relax instead?

TIA.