docker createCreates a container but does not start it
docker runCreates and starts a container in one operation
docker stopStops it
docker startWill start it again
docker restartRestarts a container
docker rmDeletes a container
docker killSends a SIGKILL to a container
docker attachWill connect to a running container
docker waitBlocks until container stops

docker psShows running containers. Use docker ps -a to show running and stopped containers.
docker logsGets logs from container
docker inspectLooks at all the info on a container (including IP address)
docker eventsGets events from container
docker portShows public facing port of container
docker topShows running processes in container
docker statsShows containers' resource usage statistics
docker diffShows changed files in the container's FS
docker historyShows history of image
docker tagTags an image to a name (local or registry)

docker imagesShows all images
docker importCreates an image from a tarball
docker buildCreates image from Dockerfile
docker commitCreates image from a container
docker rmiRemoves an image
docker loadLoads an image from a tar archive as STDIN, including images and tags (as of 0.7)
docker saveSaves an image to a tar archive stream to STDOUT with all parent layers, tags & versions (as of 0.7)