A fun game of EU4 now. I thought I was ok as Russia, what with Finland being my ally to the north and guarding there and with Lithuania being calmed by my allies Poland and Austria behind them. So I went to beat up Asians and get their land when things unravelled - first, Poland decides to start about 3 major wars dragging me in (I didn't want to lose them as an ally) and then finally Ottomans invade.
Hooray for defensive ideas though, in the end I managed to make the Ottomans bleed with attrition, smashed their big stack with mine and got Austria to help. They went from 400k manpower at the start to about 12k in the end. Didn't gain any land, but bloodying their nose like that was fun.