Tips for an American moving to Tallinn?

So, I found out on Wednesday that I will be moving to Tallinn next Monday, the 15th, for 4 or so months for work. Obviously... with the short notice, I've been scrambling to try and find out anything that I can about my new home town. Anybody have any suggestions on life in Tallinn? Things that I should see or do? Things to avoid? Etc. Any advice or help would be greatly appreciated! "Tänan!"