I came across the Aleph One trilogy release a good three or four years ago, and though my interest has come and gone at random since then, every time I come back to it I find it thoroughly enjoyable. My brief and unfinished affairs with Rubicon and Eternal have been just as good, if not better.
I've also fiddled about with map-making here and there, (mostly through Obed, though I've more recently upgraded to Weland) but I'm not sure that my creations thus far have been very good.
And lastly, I've entertained the idea of creating a full-conversion custom scenario of my own, (Marathon: Silence) but I don't intend to underestimate the amount of work it would require.
See you starside!