Yes there are... I wouldn't recommend starting with SPARC Asm though, it's nowhere near as fun as a CISC like x86, nor as easy as MIPS (which tends to be the "boring" go-to architecture CS courses use.) ARM is more interesting than MIPS and easier than x86.
I've done a little bit of x86 and I have to say I'm not very impressed by some of it. It seems like the lowest common denominator where nothing 'fun' happened.
ARM has a few ecosystem problems that I'd rather not deal with. From what I understand there is a lack of hardware discovery. ARM is more embedded then 'user' computer. Nothing is swapable.
- The ARM has a standard MMU (well, two major revs). MIPs has quite a few variants, and they involve TLB invalidation / reload. They're both worth working with.
- ARM has made some interesting architectural choices over the years, and it's worth studying what they've done. MIPs is more a static platform, not as much market pressure or will to innovate.
