I play with a couple of buddies once or twice a week, and sometimes we throw in the two sons. We've been playing CoH on the free servers. We've also played some WoW. I'm not up on the new MMOs. Are there any polished MMOs which have scalable challenges so that when I'm soloing, they are appropriate to my ability, but when I'm with my buddies the threat is higher? Bonus points if there were a difficulty slider for greater rewards/xp or instanced missions/adventures where there was a story baked into the zone. Also, no open PVP. I'm old and don't need the hassle of a 14-year-old killing me while I'm trying to have fun.
As it stands now, most MMOs don't accomodate threesomes and fivesomes in their normal content. I've thought of GW2 scaling events, but they were never very challenging.