Indeed the Dreamcast is the best machine for homebrews; mainly because there is no need for any modifications or extra hard- and software.Hereīs
a link to a popular Dreamcast site.
That said, I donīt think there is a Lynx-emulator available on the Dreamcast. Neither is there one on Nintendo DS. A sign of the systemīs low popularity I guess.
You can play stuff like CPC, NES, Mega Drive, SNES, PlayStation or Neo Geo with it though.
If you actually do happen to find one though, you donīt need to do anything with your DC to play it. Just burn the image to a CD-R (NOT RW) and play it. Most homebrews are selfbootable nowadays, if you have bad luck you get one wich is not; in that case you just have to burn a boot disc as well.
BTW, most Dreamcast images are in CDI-format, and it is much easier to find working images in that format.