Everbody likes Drush, why wouldn't you. Anyway I copied cheat sheet from some PDF as this is a drupal dump site and this way I can find it quicker and make also some additions to it.
When available, there is a shorter version of the same command in parentheses.
cache clear (cc) Clear all caches.
cron Run all cron hooks.
disable (dis) Disable one or more modules.
download (dl) Download core Drupal and projects like CCK, Zen, etc.
enable (en) Enable one or more modules.
eval Evaluate arbitrary php code after bootstrapping Drupal.
help Print this help message. Use --filter to limit command list to one command file (e.g. --filter=pm)
info Release information for a project
installcore (ic) Install Drupal core via the specified install profile. Note that updating core with Drush is not yet available. See http://drupal.org/node/434944.
refresh (rf) Refresh update status information script Runs the given php script(s) after a full Drupal bootstrap. NOTE: you can't supply absolute paths
to the script e.g. ~/Desktop/script.php won't work Desktop/script.php will
sql cli (sqlc) Open a SQL command-line interface using Drupal?s credentials.
sql conf Print database connection details.
sql connect A string for connecting to the DB.
sql dump Exports the Drupal DB as SQL using mysqldump.
sql load Copy source database to target database.
sql query (sqlq) Execute a query against the site database.
status (st) Provides a birds-eye view of the current Drupal installation, if any.
statusmodules (sm) Show module enabled/disabled status
sync Rsync the Drupal tree to/from another server using ssh.
test clean Delete leftover tables and files from prior test runs.
test mail Run all tests and mail the results to your team.
uninstall Uninstall one or more modules.
update (up) Update your project code and apply any database updates required (update.php)
updatecode (upc) Update your project code. Moves existing project files to the backup directory specified in the config.
updatedb (updb) Execute the update.php process from the command line.
variable delete (vdel) Delete a variable.
variable get (vget) Get a list of some or all site variables and values.
variable set (vset) Set a variable.
watchdog delete (wd) Delete all messages or only those of a specified type.
watchdog show (ws) Shows recent watchdog log messages. Optionally filter for a specific type.