Wargaming is a really fun hobby. Don't go about this as you got sucked by some kiddos, get in there and get some blood on your face. I don't think men realise today just how masculine tabletop wargaming is, as long as you're not making My Little Pony marines...
Are you a military officer, able to command real soldiers in battle? nah, me neither. Tabletop wargaming is my alternative. There are also many other games out there besides 40k, check out fantasy or historicals, or (gasp) other game systems if gothic scifi isn't your thing. One of my favorite opponents was a 70 something year old man. I also enjoy the assembly and painting parts. This hobby can also be lucrative to a point as well, through trading/selling, something that can't be said about very many other hobbies.