Spectate Bugs
I was a little bit surprised to see neither of these on here, but I've noticed a couple bugs with the spectate system. One of them seems to be intermittent, and I haven't narrowed down a cause yet, while the other used to be a problem, was fixed, and then returned in a recent patch.
First off, the returning bug: When entering spectate, the chat box wedges itself in the bottom corner, behind champion portraits. The only way to fix it is to open the chat as if you were typing, and manually drag it back into place - however, this only fixes it for that game, as it will plop itself right back into that corner next time you spectate. (On a related note, the last time this bug happened, the box would move seemingly a fixed amount each time, meaning that if you didn't notice it the first few times, it would eventually be completely offscreen and impossible to get back without a repair. This doesn't seem to be the case now, thankfully). I have repaired multiple times without this being affected.
Second, the time scrubber for games in spectate will pick a random game length longer than the game's current running time to show as the game time. I wish I had grabbed a screenshot last night when I saw this, as it is a little hard to explain. Around 31 minutes in, the scrubber claimed it was at 31/72:30 or so, but would not allow me to fast forward (as I was watching the game "Live" [+ 3 minute delay, of course]). I spoke with a friend about this, and he mentioned that this bug will right itself if the game goes on longer than the time randomly chosen for the scrubber.
TL;DR: Spectate has issues with the chat box and the time scrubber that need to be fixed.