It could be on your forum list just between Forum Statics and Share This Page (see screen).
I could imagine another block, which could show your most visited (most viewed) threads, most commented threads and most liked threads for 24 hours, 3 days, 7 days, 14 days, one month, all time.
On this screen you can see tabs. By clicking tabs you will change the time period. Here you can see the 10 most viewed threads in 4 hours, 24 hours, 3 days and 1 week. After the thread title is the number of views. With red color are unseen threads, with grey color already seen threads.
(Optional) I could also imagine 1 more row of tabs just above the time frame, where you will be able to select what you want to see. Most views, Most likes, Most replies, ...
Images are just for illustration to show what I exactly mean. I also found an interesting article how to make something like this wordpress. Not sure if this would be any good for anyone, but here it is.
If you like this idea, please don't forget to like this post, as this is the key to implement suggestions for XenForo as you can read here.