I mainly wrote basic games for my friends. Most popular was a two player competetive snakes variant, a bit like Tron but with traces only growing as you gobbled up food. I also wrote a 'defender' like game that enjoyed some success amongst friends.
I had no periperals or cartridges as that was too expensive. The living room TV was my monitor. It was quite a while before I got a cassette tape player, so in the early days a computer session started by retyping all code from my notebook.
I later got a ZX Spectrum which was far more powerfull, but the TI (and a HP41cv) are what got me into programming.