Thanks John M,
It indeed worked when I made a new user account, so I trashed and deleted my <user>/Library/Calendars folder, as well as <user>/Library/Preferences/com.apple.ical.plist—(backing them up elsewhere beforehand, in case something terrible happened), then re-set-it-up. (Holy cow it's easy to work with iCal after iCloud—literally seconds when it used to be at least a couple of minutes using Google Apps caldav or making an ical backup file and restoring calendars + fixing buggy events). It seems to be all good now.
A few times in my OS X history I've had issues come up where something is busted and I make a new user account that demonstrates that it's not busted universally. I hadn't even thought of doing that this time. Thanks for the idea!
May your days be merry and bright!