play <something> - I really love this one, it will try to make an educated guess on what you would like to listen. You may say "play pink floyd", "play dark side of the moon" or "play us and them"
shuffle <something> - same as above, but will shuffle results
shuffle - shuffle current playlist
shuffle all/everything - yo kids! This one's for you!
select/insert artist <name> - will play or add to current playlist all songs from <name> artist
select/insert album <title> - will select songs from such album
select/insert track <title> - will select track(s) of such name
select/insert genre <genre> - will create a playlist consisting of tracks of such genre
search/find - open search text field
search/find <something> - search xeno database
Of course it is not perfect, and depends highly on your us-English accent.