Couples yoga can be fun. You get strength and flexibility work, but it is more than just doing the exercises together, as it tends to be a style that promotes connection, and communication and trust.
Please note that I am not talking about ‘sensual’ or ‘intimate’ yoga…. just a style of yoga practice in which the stretches and holds are done in a way in which two work together. You do need to read the description of what is in the book or dvd carefully to make sure you are getting what you want.
Ganga White and Tracey Rich taught partner yoga back in the 70s, and I have their book, but I don’t know that it is still available. However, there are a number of books and videos one can get. Actually they are in Santa Barbara, if you are ever out that way.
It probably makes sense not to tackle it without at least some familiarity with yoga generally, and particularly helpful to do a workshop with an experienced teacher first.
It really depends on what they like and what their relative fitness levels are.
We have a CrossCore that hangs in our laundry room and both my husband and I use it. Although he sometimes takes my bootcampy classes, we don’t typically work out together, but that would be a good equipment to work out on together as we can easily change the exercise angle and do the same exercise simultaneously, regardless of who is stronger in what exercise.
It depends on their fitness level and goals and also what they really like to do together. The range and level of exercises can vary from something very simple to very complex (I can think of a number of exercises and routines they can do together but without knowing the above information it’s difficult to give you any suggestions).
Hopefully you know the couple’s fitness levels, and the equipment they have available at home to work with. There are many fun bodyweight exercises you can have the pair alternate together for time such as planks, squats, wall sits, pushups, stairs, lunges, etc…
Also, here is a good link from ACE (I see that you are ACE certified, so you may have already seen this one):
Hope some of these ideas give you some inspiration!
Also, here is a link for many posted here on IDEA. There are some great ideas here!