While the federal government is shut down, many federal websites will not work. One can still get cached copies of NSF solicitations, but there's no guarantee that they will stay up. Here I have put up some ones for programs with upcoming deadlines, as well as the grant proposal guide. It is not clear yet what will happen with deadlines (NSF will release guidance after the shutdown, according to its skeleton website); if it were me, I'd prepare everything for the original deadline just in case.
- Doctoral dissertation improvement grant (original deadline Oct. 10, 2013): PDF
- Graduate research fellowship program (original deadline Nov 4 - Nov. 8, 2013, depending on field): PDF
- Grant proposal guide (the form with detailed instructions about formatting): PDF (11.4 MB)
The Internet Archive also has older versions of the NSF website saved: see here for a list of funding opportunities, for example. The only trick is that the last version they saved was when the site was down for maintenance, but you can move the date back to an earlier version when they had content.