I can attest to this as well. Was in a game and at least 3 other players on my team were experiencing the same issues. Ping started off exceptionally high (around 180, I normally have between 70 and 80) and would shoot upwards of 300. I know computers and networks and tried all the normal tricks; nothing streaming, downloading, etc. Network analyzers show my connection is fine, so something is off. I don't know if others fall into my boat or not, but I had major issues when you guys switched over the chat program which caused all those "PVP.NET chat disconnected" issues.
Hope Riot gets on this soon, cause the game is unplayable like this.