In 2007 I split from my then wife and consequently was a single father of 3 young children (ages 6, 3 and 1 at the time). My kids were the most important thing in my life so the 50% of the time I had them I took great joy finding things to engage their developing minds. The other half however was a bit of a challenge while I learned to find myself as an individual but that is a topic for a different day.
In the interest of saving money we ate at home for nearly every meal. Their mother was a rather picky eater and in my efforts to combat this I tried to expose the kids to a broad variety of foods. Like any experiment there were some successes and some failures. One of the more cleaver ideas (I think) was to pick themes for meals.
Every Sunday we would go grocery shopping and buy food for the next week but the best part was trying to find items that fit our one experimental meal each time they were at my house. The themes could be as simple as an origin (Italian, German, Korean. etc.) or a shape (round, square, spirals, etc.) but my favorites were when we focused on a specific color.
These could be truly challenging like when we had squid ink pasta, black rice with a side of black berries and black olives, chocolate milk to drink and Oreo pudding for dessert. Yes, I realize they don't all fit together per se beyond the color but remember the focus was on trying new things so they would sample a little of each.
For blue we had things like blueberries, blue corn chips and blue Kool-Aid but when we ran out of naturally occurring items of a specific color I would resort to food coloring. "Why yes, this cabbage is naturally blue you should try it!" Some colors like red and white were far easier but still I tried to find new menu items to keep their pallets guessing.
For years after we stopped this the kids would talk about it fondly which always filled me with pride. Sad to say I think I failed at keeping them from turning picky though. They have different levels of interest in food variety but suffice to say they are far more limited than I'd prefer. Hopefully time will yield a more robust interest in food diversity but at the very least we have some fun memories to look back on.