I'm a sucker for a clever piece of stationery, and these rubber stamps from Present & Correct certainly fit the bill. Each one measures 50mm x 30mm (~2" x 1.2") and features a design based on a particular form, graph, or postage template that you fill out yourself:

1. Postmark
2. Checklist
3. Label/luggage tag
4. Printer marks
5. Soviet postcode
6. Form box
7. Pie chart
8. Air mail
9. LCD number display (like an alarm clock or microwave)
10. Dot matrix

Pretty neat, eh? The stamps are £6 (~$8 USD) a pop and ship from the UK.