envbot is an advanced modular IRC bot coded in bash. Features include SSL, IPv6, modularity (with several good modules already), transport modules (including OpenSSL, GnuTLS, netcat, etc.), loading/unloading/reloading of modules at runtime, rehashing configuration at runtime, advanced access control, and much more.
Sshbak is very simple but powerful and secure remote backup utility. It performs a fast and comprehensible daily (usually) backup of multiple machines via remote SSH connections. The result is a simple set of tar+gzip files. It supports the backup of piped program output (allowing remote backup of mysqldump or pg_dumpall results), parallel backup of different machines, and more.
RRDutil is a a tool to collect statistics (typically every 5 minutes) from multiple servers, store the values in RRD databases (using RRDtool), and plot out pretty graphs to a Web server on demand. The graph types shown include CPU, memory, disk (space and I/O), Apache, MySQL queries and query types, email, Web hits, and more.