If the "node.js' awesome architecture" is referring primarily to its event-oriented/asynchronous architecture, Tcl has an incredibly robust event-oriented mechanism[1][2] for those interested in playing with it. Looking forward to seeing what shakes out in this arena. Culturally, Tcl has been heavily event-oriented[3] for a long time, so it'll be interesting to see what others chose to do with it.
[1] http://www.beedub.com/book/2nd/event.doc.html
[2] http://wiki.tcl.tk/489
[3] http://news.ycombinator.com/item?id=399670
edit: footnotes