7 types of light bulb

1. Incandescent
2. Halogen
3. Fluorescent
4. Compact Fluorescent
5. High-Intesity Discharge
6. Low-Pressure Sodium
7. LED

7 pages on facebook that they suggest I might like that I really don't

1. Stereophonics
2. Billy Joel
3. Desperate Housewives
4. Guns 'n' Roses
5. England 2018 Official World Cup Bid
6. Only Fools and Horses
7. Sleeping in Tents

7 hardwoods ranked by Janka hardness

Janka hardness measures the force required to embed an 11.28 mm (0.444 in) steel ball into wood to half the ball's diameter, in pounds force.

1. Lignum Vitae - 4500
2. Patagonian Rosewood - 3840
3. Brazilian Ebony - 3692
4. Brazilian Walnut - 3684
5. African Pearlwood - 3680
6. Bolivian Cherry - 3650
7. Lapacho - 3640

7 arcade racing games

1. Gran Trak 10 - Atari (1974)
2. Night Racer - Micronetics (1977)
3. Turbo - Sega (1981)
4. Pole Position - Namco (1982)
5. Out Run - Sega (1986)
6. Hard Drivin' - Atari (1988)
7. Virtua Racing - Sega (1992)

7 largest cities by population

1. Tokyo - 33,800,000
2. Mexico City - 22,900,000
3. Mumbai - 18,042,000
4. Sao Paulo - 17,711,000
5. New York City - 16,626,000
6. Shanghai - 14,173,000
7. Lagos - 13,488,000

7 answers we got right in this week's University Challenge

1. Primate
2. Grand Theft Auto
3. Parapit
4. Black Hole
5. New South Wales
6. Lactose
7. O

7 eusocial creatures

1. Wasps
2. Ants
3. Bees
4. Termites
5. Aphids
6. Thrips
7. Naked Mole Rats