this looks like a nice enough app, but if you want all the functionality of MagiCal, plus the option (but not the requirement) to show CPU usage, memory usage, hard drive usage, hard drive activity, network usage, network activity, and a temperature gauge for each CPU in your machine, all in your menu bar, all in a prettier and more configurable package than MagiCal's, and all for free, you owe it to yourself to check out iStat Menus. it may be more than you want/need (i actually only use the network activity and bandwidth indicators and the clock/calendar myself), but even if you only use the clock/calendar, i bet you'll be more impressed with it than you are with MagiCal.

i'm not affiliated in any way with...uh...whoever makes iStat Menus...i'm just a really happy user.

whichever one you settle on, enjoy... :)