The World Clock – gives you the current time in all the countries,
Weather Underground – provides detailed current worldwide weather information and forecasts
Wikitravel – like wikipedia but just about traveling. Almost every city has it’s own free travel guide.
Couchsurfing – the best way to get to know a country and its locals
Nicetranslator – a fast and easy online translator, you can add multiple languages. Love it!
For fun – 18 moments every backpacker experiences