Tunnel MTU and MSS calculator
Here it is: encapsulation overhead calculator
Allows you to quickly see the MTU and TCP MSS of tunnels with different combinations of encapsulated and encapsulating protocols (GRE, IPv4, Ethernet etc.).
Random OBEY message generator
Here it is: OBEY
If you watched John Carpenter's They Live movie, you know what it's all about. Features most or possibly all messages seen on billboards in the movie.