If you have a linux box that's always on on your network, you can throw in a simple cron entry to curl a dynamic dns provider (entrydns.org works pretty well in my experience), which updates their dns entry for a url you set. Set up OpenVPN on your router, VPN to the URL, voila, access to your self-hosted services.

You definitely shouldn't expose most of these things directly to the net, they're not always bulletproofed as much as one would like.