Bake Simulations and Caching
You can bake many types of simulations: rigid and soft body, particles, dynamically driven, objects with expressions, etc.
Baking Rigid Body Dynamics
Make objects, select them and make them Active or Passive Rigid Objects (Dynamics Rigid/Soft Bodies)
Edit Menu - Keys - Bake Simulation - Options
All keyable: All keys will be baked
From Channel Box: lets you select which attributes you want to bake
Time Slider: It will only bake for duration of the time slider
Start/End: You can set start and end frames to bake
Sample By: 1 = set key on every frame, 10 = set key on every ten frames
Look at the Graph Editor
You can see I set the Sample By to 5.
Open the Outliner
Make sure the Shapes has a checkmark
Open each shape by clicking the +
Remove the Rigid Body node by deleting it.
Baking (Cache) Cloth Simulations
You don't really "Bake" a cloth simulation, you "Cache" it.
Create a new Cache after you have already made the cloth simulation and it is how you like it.
It is located in the nDynamic Menu set
Don't forget to Delete it if you don't need it - it takes memory.
Always create a Cache before rendering otherwise the "run-up" time required to render your simulation will increase the more frames you have.