Aroma Foot Massage
One of the best ways to explore Hanoi is by walking around the streets. If you are tired after a long walk and happened to be at the famous St Joseph's Cathedral, there is a foot massage shop at the row of shop houses just next to the cathedral called Aroma Foot Massage. I went for a foot massage here for about 1 hour, and it was quite good and the price is very cheap (see the second photo for the prices of the different types of massage here). The place is air-conditioned which is very relaxing if the weather is hot outside :)
Explore the villages (I)
Hanoi is well worth spending a week, but what if you become bored by it? Why not check out the villages in the vicinity of Hanoi? They will provide you with a unique view of Vietnam's rural life and you'll be amazed how untouristy this country can be. Not to mention the incredibly friendly people...
The best way to visit the villages is by motobike. I believe that there are organized tours that can be booked somewhere in the Old Quarter, but I always preferred going with a Vietnamese friend of mine. For German-speaking people: Students of German are glad to show you around and guide you through Hanoi and the villages (see another off-the-beaten-path tip). First thing to do is get a motobike - go to Hang Bac street and rent one. There are plenty of shops and if you bargain a little, you'll get a quite reasonable price. Second, get yourself a map of Hanoi. Good ones can be purchased in Trang Tien street in any one of the bookstores. Third, practice driving! As stupid as this sounds, Hanoi's traffic is awful (though very funny if you finally find out how to survive it) - your normal driving skills won't be enough. In the countryside, the situation is better, but still not really safe. If you've done all that, you can finally start your exciting tour through the villages and the countryside.
It's not just one shop, it's a whole street full of silk shops. Each one sells silk clothes as well as the fabric itself so that you can have a shirt or a dress tailored somewhere else. I guess that there are about 60 shops. I propose buying the fabric only - it's possible to have a shirt or anything else tailored in Van Phuc village, but if you know a tailor, go to him or her. However, buying a silk scarf fro Grandma or a silk necktie for Dad cannot be wrong... It's a matter of bargaining - there are not too many tourists in Van Phuc, so prices have stayed relatively low. For the amount of silk that you need for a shirt expect to pay between 50000 and 80000 VND. It's best to come with a Vietnamese friend as they might bargain more successfully. Also, most of the vendors are not speaking English.
50/50 split between Vietnamese and expats, this has to be one of the friendliest spots in Hanoi. Absolutely packed. Good place to grab a beer alone or with a few friends. Bring a waterproof phone. Last time I went, someone tried to move a table and saturated my jeans...and my phone.
Reunification Express - Hanoi to HCMC
We travelled overnight on the Reunification Express train from Hanoi to Hue and it was good fun! You can share a sleeping compartment with 4 bunks (1st class) and 6 bunks (2nd class) (best to take your own sleeping sheet for both classes) and in the morning you get great views of the countryside! Good idea to take your own food and drink on board as the food served didn't look too appetising! The train journey we took from Hanoi to Hue lasted just under 12 hours and the soft sleepers (1st class) cost around £14/$28 one way per adult. Best to book tickets at the train station a few days in advance if possible. Trains also run down to Ho Chi Minh City from Hanoi, stopping at various places along the way.