SourceForge http://www.sf.net/ - aka SF - is an ambitious attempt to provide open source projects with freely available source code , bug, and request management, mailing list support, software distribution, and more. The effort has over 20,000 projects at this time.
A number of As of mid August, 2001 the massive collaborative project support site at SourceForge [L1 ]/[L2 ] has (at least) 250 projects in (or using) Tcl and Tcl/Tk. Some stay in the top downloads, or high-activity category. This page is started because so many projects have been moving to SF.
Browse these projects from their trove list at:
http://sourceforge.net/softwaremap/trove_list.php?form_cat=182
Free to OpenSource developers, and development collaborators, SourceForge provides:
But rather than advertising SourceForge here, go browse the projects, or start your own, and announce it below:
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etc.
There is also a small code snippets library there:
http://sourceforge.net/snippet/browse.php?by=lang&lang=11
Please note that not everyone is perfectly content with sourceforge:
http://www.advogato.org/article/376.html
http://www.advogato.org/article/357.html
You may not agree with them, but they mention some reasonable points.