K7

Create a phone number online. You can personalize its greeting to receive callers. When they do call, you receive e-mail notifications, and you can download the message to be played on your computer. Now you can stop wasting so much time checking your phone, your fax, and your answering machine.

Deezer

Perhaps the best free music site ever. No download is required, and a wide variety of music is readily available. If you can't really decide what to listen to, start a smart radio based on some of your favorite songs. Deezer will play songs similar to the ones you chose.

Spy Pig

Have you ever sent an e-mail to someone and wondered if the recipient has read it? Now you can be more than curious, and actually find out with SpyPig.

Polycola

Use multiple search engines at once on one site with Polycola. You'll sure to be find what you're looking for. Be sure to check out FireFox HOT. Now you can add PolyCola to FireFox Search Bar with just one click.

Sparknotes

This site is for the students. Notes are given here for almost every work of literature there is. You can get your test prep here, as well as access a very well done section about Shakespeare, which includes his sonnets and plays. Did I mention that his full plays are on the site, and that they're translated so that the average person can read them?

Calories Per Hour

Keep track of all of your personal fitness here. Calculate your BMI, calories burned in a day, weight loss in a day, and much more. There is also a diet and weight-loss section here. Great for those who want to calculate calories and nutrition, as well as find some great health tips.

Free Rice

Think you're smart? Think you're smart enough to feed hungry children? Then check out this site. Play a simple word game to donate rice. A word will appear, and ask you for the definition. Every word you define correctly is 20 grains of rice donated. Expand your vocabulary while feeling good about what you're doing.

Kongregate

For many people, games are great for relieving stress, competing with friends, or simply just to kill time. Kongregate is a site that contains most of the best free online games out there. Unlike other gaming websites, this site contains badges, which are attainable after completing an achievement in a game. This may not seem like much, but it definitely has its advantages. Now you have a clear cut idea of your progress and it gives you tangible goals to work towards in a game.

Prize Rebel

If online games aren't your thing and you prefer console games more, this site is for you. By completing free offers, you earn points, which you then can redeem for various gaming equipment, shipped straight to your house. Don't believe me? There are many testimonials, and I myself have received a Nintendo DS game.

• Search for: [word]
  
  This is the standard search most users start with on the site. It returns as many results as possible on your [word], based on the links to that web page and the number of page hits it receives.
• Search for: [word] [word] …
  
  This search is like the above example, except it includes two or more words. The only difference is that the word order affects the basis of the search.
• Search for: [verb] [noun1] OR [noun2]
  
  Search outcomes for these words are [verb] [noun1] and [verb] [noun2]. Personally, I don't find much use for this.
• Search for: “[phrase]”
  
  You can search for any word or phrase you put in the quotes, and will only receive results for the exact phrase detailed in the quotes
• Search for: [word1] -[word2]
  
  This search, in my opinion, is the most useful one. It searches for the first word, but omits any results with the second word. This is extremely pertinent when searching for a word with multiple meanings, such as salsa. If [word1] is salsa, and [word2] is dance, then you will most likely get results about the edible salsa, and not the dance.
• Search for: [word] ~glossary
  
  Doing this search will mean receiving glossaries about the [word]. It's useful when looking up information.
• Search for: [word1]-[word2]
  
  This searches for all forms of the hyphenated words, such as the words together without a space, the hyphenated without a space, and words separated by a space.
• Search for: Define:[word]
  
  This is pretty self-explanatory. It searches for all definitions of [word].
• Search for: [number] + - * / [number], [num] % of [num], [num]^[num]
  
  This performs math for you.
• Search for: [units1] in [units1]
  
  This converts units for you. Example: 100 lbs in kgs.