I'm 42. I've had such a project since 14 or so, more than a 1/4 century. There has been long stretches of inactivity, exp lately. But, I've used it to learn many languages, GUI frameworks, OOP, the non-existence of silver bullets (aka OOP ain't all that), and many other topics/skills. Originally started in K&R C, then Turbo Pascal, Perl, C++ (it was new and exciting when I was in college), back to Perl, finally and for the long time now Python (with which I made more progress in shorter time than all other efforts/languages combined). Lately (last couple years) been toying with writing parts in Erlang.

I've long since accepted I'm not finishing this. I sort of don't want to. It's an old friend, I would miss if it went away.