What leisure activities did the Buddha partake in? I find this guy fascinating but during that time I can only think that he may have played eye-spy on the banks of the river Ganges or flicked pomegranate seeds at the bodhi tree. I'm probably way off here though with my silliness.

In all seriousness, what was leisure to him?
I recommend a few words:


divāvihāra -- for example the page-long description of that here which starts ...


  an expression which ... I consider to correspond to the “day’s abiding”, divāvihāra, mentioned in MN 35 at MN I 229, 23, instead of intending a “heavenly abiding”.


It's used in many suttas to indicate what monks do (or at least, where or when or for what purpose they go somewhere) in the afternoon.

That footnote also mentions some activities like "the divine eye" -- which is mentioned in suttas sometimes, in the context of the Buddha seeing that someone somewhere might benefit from his help -- I'm not sure what the best example of that is, Ud 3.3 was the first I find ("Then, encompassing with his awareness the awareness of the monks staying on the bank...").
also, sukhavihāra (dwelling pleasantly)
suññatāvihāra -- e.g. from MN 121


  ‘Ānanda, these days I usually practice the meditation on emptiness.’
  ‘suññatāvihārenāhaṃ, ānanda, etarahi bahulaṃ viharāmī’ti.


Ditto in MN 151, which also calls that
Mahāpurisavihāra ("the meditation of a great man.")
Eventually, in DN 16:


  Now I am frail, Ananda, old, aged, far gone in years. This is my eightieth year, and my life is spent. Even as an old cart, Ananda, is held together with much difficulty, so the body of the Tathagata is kept going only with supports. It is, Ananda, only when the Tathagata, disregarding external objects, with the cessation of certain feelings, attains to and abides in the signless concentration of mind, [19] that his body is more comfortable.