I’m not particularly impressed with any of the available Ubuntu clock widgets. Luckily, I found a better option. If you want a nice clock in Ubuntu, you may choose to:
1. Install Screenlets (Applications - Ubuntu Software Center)
2. Run Screenlets (Applications - Accessories - Screenlets)
3. Launch an extra copy of the 'Output' screenlet (Select 'Output', then press 'Launch/Add')
4.Configure the 'Output' screenlet with these settings: (Right-click the grey box that appeared somewhere on your desktop.)
a. Under Properties - Options - Screenlet
a.i. Scale: 5
b. Under Properties - Options - Options
b.i. Command to run: date +%I:%M
b.ii. Update interval seconds: 15
b.iii. Width: 50
b.iv. Height: 25
Now drag it to wherever you want, and enjoy.