That's an interesting tease for an Apple event. What could be they be referring to?
Not the Mac Mini. It's one of my favorite Apple things, but it's also their least important (to them) product. There is zero chance it's headlining an event.
As everybody else has noted, the logo appears to be a throwback to the classic rainbow-colored Apple logo from the 70s, 80s, and 90s. It'd be cool if they were refreshing their branding. I give that possibility a "maybe," though I also don't think they'd throw a press party for that alone.
My guess is that the colors are a reference to colored Apple products. I'm almost embarrassed to admit that I hope this is true, but... I do. The colored aluminum on the iPods of yore was cool; imagine a colored anodized MacBook in your color of choice.
Things I Predict We'll See
- OSX Yosemite, obviously.
- Updated iPad Air, obviously.
- Colored MacBook Pros and/or MacBook Airs.
- Retina Thunderbolt Displays and/or iMacs.
- Minor Mac Mini refresh. This might be a "silent" update where they don't mention it in the presentation, but it gets rolled out in the online store after the event.
- A "real" server-oriented Mac Mini. Max of 32-64GB of RAM instead of the current 16GB. ECC RAM for increased reliability. Lights-out management. Aside from a bump to 32GB I don't think these are even possible; the Mac Mini's form factor means it's pretty much always going to have "laptop guts" and not one of Intel's bona fide server-oriented chipsets.
- Some possible way that a Retina Thunderbolt Display could work with my 2011 MacBook Pro @ 60hz. Again, I don't think this one is physically possible.
- Free hookers, world peace, pizza.
- A revelation that the A7/A8/A9 chips are somehow hardware-optimized to run their Swift programming language at obscene speeds, faster than C or hand-tuned assembly, and that they're turning this feature on for everybody today. Yeah, this is even less likely than the hookers, peace, and pizza.
- Some kind of renewed Free / open source software commitment.