A few bugs, glitches, and oddities
Kog'maw loses attack speed on death but regains it after being revived.
Phantom dancer counts every time that it prevents a death, rather than every time it prevents a death within a few seconds. This should really be changed to count a stack every few seconds.
You can see other people's champs and masteries through a bug. To perform this bug: Go into the profile page of the person's champs you wish to view. Swap back to your profile page, and then very quickly click on your champions page. You should now see the other person's champs, masteries, and all of that stuff. @Rito, this should be implemented as a feature rather than as a bug as it is now.
Graves' dash interrupts Skarner's ult cast and makes it so that, if timed correctly, will stop the ult from going off. This does not make Skarner's ultimate go on cooldown. (The sound and animation for Skarner to ult start, but do not go further than that. Had this happen 2 times in a row when versing a Skarner as Graves.