Clock...back in time for dinner.

Speed...fun.

Odometer...bike maintenance.

Cheap $5.44 toy with free shipping works great 4 me. Takes a little tinkering to secure it to the bike, but the hardware/software is bug-free. Used one LR44 battery. Unit is very accurate if properly calibrated. My units shows an error of 0.006 mile for each mile travelled.

http://www.dealextreme.com/details.dx/sku.24075