ContikiBBS is a tiny, little and text based bulletin board system (BBS) for the Commodore 64 home computer and a compatible Ethernet cartridge (e.g. TFE, RRnet, 64NIC+). It can be accessed through a standard telnet connection and currently provides basic BBS functionality (select from multiple boards, post/read messages, page sysop).
Source: http://cbm8bit.com