2008's 'Let's Rock' event

Today brought a much-expected invitation for Apple's news event next week. It's just the latest in a long series of invitations from Apple that have provided a clue or two about what's to come.

Now is as good a time as any to take a quick look back at invitations to special Apple events. Some were not so subtle, while others added outright mystery about what was to be announced.

CNET has put together a quick rundown of some of the most interesting invites to come in the past few years, as well as what was announced at each.

Seen here is Apple's "Let's Rock" event in September 2008. The event brought the introduction of HD TV shows and iTunes 8, with its Genius recommendation feature. Hardware-wise, the company introduced its fourth-generation iPod Nano, second-generation iPod Touch, and new in-ear headphones.

Credit: Apple