I sent in a mail-in / absentee ballot, which was much like filling out a Scan-Tron form for a test in school. Choosing which circles to fill in was a bit tricky though. (Fill in #92 to vote yes on Proposition 33; fill in #97 to vote no on Proposition 34; etc.) I triple-checked everything.
An interesting bit was I got a call from a 'bot at the Los Angeles County Registrar's office Sunday. It more or less said "If you've already mailed in your ballot, disregard this message. If you haven't mailed in your ballot, it's too late. Drop it off at a polling place."
Also on the radio this morning it said that 51% of voters in CA are mail-in for this election.