We had our baby shower just 3 month ago :-)
Since we mostly planned our own baby shower, getting the list of invitees was pretty easy. If you are planning for someone else, this might be the next puzzle piece to solve.
The biggest challenge we had in planning was to find a room suitable for the event. We expected between 20 and 30 people and could not host at home for various reasons. Local Event halls where too large and some did not allow for self-catering. We did want to avoid the expense of a restaurant. Some local Churches might have had something fitting but since we are not members anywhere that fell through as well.
Places we looked for rooms: Local fire department, American League Post, local Churches
In the end Friends offered to host the party and had built an amazing diaper cake and nicely decorated their home. We had not planned much in terms of activities and followed through with even less...
We did bring food and drinks to lower the burden on our friends.
what we had planned:
- measure around the bump and have people guess. Closest wins :-)
- we bailed on the "baby food" game - our hosts are a bit sensitive to mess...
- there was some game with clothes pins - forgot how it worked

you can check here for some more games:
http://www.momtastic.com/life/541581-baby-shower-games/#/slide/1Besides that - I designed our own invite cards. Still need to send out thank you cards.
What was recommended was to take pictures during unwrapping of gifts so you can keep track of who gifted what. This allows a more personal thank you card.
In the end we had all of our friends there and it was a beautiful party. Followed by a beautiful Baby Girl :-)
Not sure how much this helps...
Hughs - Sarah