These estimates may be helpful when you're trying to determine if your numerical answers makes sense.  They may also come in handy if you need to make an estimate or assumption in a problem.
 

Typical Distances  
Diameter of the known universe 1026 m
From earth to the nearest galaxy (Andomeda, M31) 2 x 1022 m
Diameter of our galaxy 8 x 1020 m
From earth to the nearest star (thatís not our sun) 4 x 1016 m
From Pluto to the sun 6 x 1012 m
From earth to the sun 1.5 x 1011 m
Radius of the earth 6.4 x 106 m
Height of Mt. Everest 8848 m
Length of a football field 102 m
Height of a person 2 m
Diameter of a CD 0.12 m
Diameter of a period in our text 5 x 10-4 m
Diameter of a red blood cell 8 x 10-6 m
Diameter of a virus 2 x 10-8 m
Diameter of a hydrogen atom 10-10m
Diameter of a proton 2 x 10-15 m

Typical Masses
Galaxy 4 x 1041 kg
Sun 2 x 1030 kg
Earth 6 x 1024 kg
Space Shuttle 2 x 106 kg
747 airplane 3.5 x 105 kg
Elephant 5400 kg
Automobile 1200 kg
Person 70 kg
Bowling ball 7 kg
Baseball 0.15 kg
Honeybee 1.5 x 10-4 kg
Raindrop 2 x 10-5 kg
Red blood cell 10-13 kg
Virus 10-20 kg
Hydrogen atom 1.67 x 10-27 kg
Electron 9.11 x 10-31 kg

Typical Times
Age of the universe 4 x 1017 s
Age of the Earth 1.5 x 1017 s
Existence of the human species 6 x 1012 s
Human lifetime 2 x 109 s
One year 3 x 107 s
One day 8.6 x 104 s
Time between heartbeats 0.8 s
Collision time for batted ball 2 x10-3 s
One cycle of a visible light wave 2 x 10-15 s

Typical Speeds
Light 3 x 108 m/ s
Earth orbiting the sun 3 x 104 m/ s 
Concorde airplane 710 m/ s
Terminal speed of a sky diver 60 m/ s
Pitched baseball 45 m/ s
Running cheetah 28 m/ s
Olympic sprinter 12 m/ s
Terminal speed of a raindrop 7 m/ s
Brisk walk 1.3 m/ s
Snail 10-3 m/ s
Human hair growing 3 x 10-9 m/ s
Continental drift 10-9 m/s

Typical Accelerations
Ultracentifuge 3 x 106 m/ s2
Baseball when batted 3 x 104 m/ s2
Car crashing into a wall at 60 mph 103 m/ s2
Bungee jump 30 m/ s2
Gravitational acceleration on surface of earth 9.8 m/ s2
Emergency stop in a car 8 m/ s2
Gravitational acceleration on surface of moon 1.7 m/ s2

Typical Forces
Saturn V rocket 3.4 x 107 N
Main engines of the shuttle 2 x 106 N
Pulling force of a locomotive 105 N
Weight of an adult 1000 N
Weight of an apple 1 N
Weight of an ant 1 x 10-3 N

Typical Energies
Annual US energy use 8 x 1019 J
Mt. St. Helens eruption 1018 J
Thunderstorm 1015 J
Jet aircraft moving at 500 mph 109 J
Energy released in the explosion of 100 pounds of TNT 2 x 108 J
Chemical energy in one gallon of gas 108 J
Chemical energy in a large pizza 2 x 107 J
Human food intake/ day 107 J
Car travelling at 60 mph 106 J
Energy required to melt an ice cube 104 J
Electrical energy used to light a 100W blub for 1 minute 6 x 103 J
Football linebacker running at a quarterback 4.5 x 103 J
Kinetic enegy of a person walking 50 J
Kinetic energy of a flying bee 2 x 10-3 J
Work to turn a page of a textbook 10-3 J
Kinetic energy of a moving snail 5 x 10-7 J
Energy required to break a bond in DNA 10-20 J