User Whatakuai has made a delightful 3d model of a tea cup with one twist:

It has an angled bottom so when you tilt it in one direction your tea is getting infused; if you tilt it the other way around the infusion stops and you're ready to drink it.

That's really convenient if you tend to drink a lot of tea in leafs (without bags) as it removes the hassle of dealing with tea-tongues, tea-eggs and filters and stuff. And you won't make a mess dripping tea around when infusing/re-infusing/defusing... damnit I wish I had a video like one of those shabby infomercials for household products that primarily show how unhandy people could be; you know, something like that just with spilling tea:
http://thefw.com/files/2012/10/missingsoda.gif

Long story made short:
Whatakuai's design is really nice for a rendering but it's hardly FDM-printable. The separate filter doesn't hold and has a bottom-surface far from usable; bad overhangs as well... so I decided to union both parts into one. Additionally I smoothened the outter surface as it's a bit coarse (I kept the coarse surface on the inside because it looks nice that way... and I'm super-lazy) as well as one edge of the filter which was a bit too "edgy" for my taste.

I've also uploaded a version with manual support for all the cura users which are not able to restrict support to factors different than overhang angle (I have no idea if other slicers give more options here but I guess so). However it prints okayish and usable without support but the angle is too steep for a perfect surface finish. At least on my cheap printer.

I also plan to decrease the hole-size of the filter one day because my favourite teas are cut pretty fine and tend to fall through the bigger holes.

edit:
just for the sake of completeness (and to honor the original designers Laura Bougdanos and Vesa Jaasko), here's where you can buy the real stuff:
https://tipcup.myshopify.com/products/tipcupmeetsmagisso-tea-cup-2?variant=13230935236#
They even won a design award for the cup - which doesn't surprise me at all.

24.03.2017: decreased filter holes size, made outter surface smoother and fixed some minor stuff. Ditched the support-version as it didn't turn out significantly better than with cura's support.