Two of my favorites!
9. TripIt – The service will scan your email inbox multiple times a day for any travel plans and automatically imports them to your TripIt itineraries without you having to forward any email message to TripIt.
If you already have an existing trip with overlapping dates, TripIt will add the plan to your trip else it will create a new trip.
10. Boomerang – With Boomerang for Gmail, you can compose an email now and schedule it to be sent a later time. Thus you can easily schedule birthday notes when you have time to write them and have Boomerang dispatch them at the right time.