Attendees hold signs (white boards, chalk boards, custom signs) and write their own personalized message.  The Daily Beast utilized this to connect with fans at their Hero Summit.  Signs were used to individualize each photo and on site prints left each with a memorable takeaway.

Create exclusivity and buzz by only providing a select few with the desired hashtag.  Don’t want everyone in attendance to know your hashtag?  This secretive option can be used to create an exclusive event with increased privacy around the photos that are taken and shared.  

Hang photos up to create a simple Instagram wall.  The displays can be creative and attractive to fans.  Krug Champagne utilized this at their Krug House event by creating a custom Instagram wall using string, clothesline clips, and printed Instagram and Twitter photos.  They also added a chalkboard sign with instructions.

Attendees must find certain objects to take photos with using the event hashtag.  Vector Marketing created buzz at their RDC Conference by encouraging participation for the photo scavenger hunt.  Photos had to be taken next to specific items for points.  Contests/giveaways compliment this well.

Take all tagged videos and compile them into a creative marketing video.  Or use video to generate testimonials for a product or brand, the 15 seconds allowed on Instagram is usually plenty of time for one to explain why they like or prefer a certain product.  These can then be repurposed and displayed creatively.