Things Wolfram Alpha will Tell You in One Click

1. sum(x,1,100), x^2

2. D Flat Mixolydian Scale is also known as "Khamaj Thaat" (and what it sounds like).

3. A graph of the overlapping lifespans of Charles Dickens, Emily Dickinson, and Stephen Wolfram.

Sadly Alpha does not know that 1, 4, 9, 6, 5, 6, 9, 4, 1, 0 is the periodic cycle of the terminal digit of integer squares, something mathy it might learn by consulting the OEIS.

Also, google currently provides better results on "aleph null", which Alpha just can't interpret (even in other forms, like aleph-0, etc). Google's third link for aleph null gives an excellent overview of the topic, by sending you to the Wolfram Math article on it.

Still looking for others.

UPDATE: Fixed the link to the terminal digit of squares to reflect the actual search term, thanks EP.