We have a couple of birthdays coming up soon and my partner will be 30 weeks pregnant,
For the birthdays there is planned Ten Pin Bowling, and Paintball.
Are these sports ok to do whilst at that stage of pregnancy?
Ten pin bowling should be no problem at all, but I would encourage the use of extra body protection for paintball, mostly as getting a paintball to the stomach can be bad enough without it also impacting on stretched skin or an unborn baby.
Aside from that I would heartily endorse @Peter's answer. My wife continued with sports (including rock climbing) until she got big enough to prevent her moving easily, and even then would still go for 8-10 mile walks.
If she has no special health issues, her pregnancy is OK, she is in good condition and has been doing more or less regular physical activity up to now, then why not, as long as she feels OK with it. It is definitely possible to do even vigorous physical activity throughout most of one's pregnancy - if one is in good health and has been practicing regularly already before her pregnancy.
Bottom line is, as usual, she is in the best position to sense her own internal feelings and wellbeing, so (assuming the above conditions are fulfilled) if she feels it's OK, let her join the party. However, if midway into it she feels it's enough for her, she can stop.
Week 30 is just in the third trimester, so the tummy (usually) should not be that big yet to stop her from moving, or to change her balance significantly.
Disclaimer: I am not a medical doctor, this is just my 2 cents worth. If in doubt, consult a doctor.
In the general sense, it is okay to engage in sports while pregnant, presuming she's had a healthy pregnancy and was physically active before getting pregnant as well. However, the pregnant belly is also somewhat delicate and it is not recommended to engage in any sport where projectiles or balls or feet or whatever might slam into the stomach at high speed, or where the risk of injury is significantly high as a serious injury could add complications to the pregnancy, so I would be inclined to say that while bowling is safe, I wouldn't recommend paintball.