Multiple controllers on 1 page

[eluser]WanWizard[/eluser]
Not too complicated, if you think in widgets and loose coupling.

I use modules, where module controller method produce html (via module views) that generate a widget. The local in the main app controller inserts those in a template.

You can do that in CI, but you'll need a modular solution, as native CI doesn't support controllers calling controllers, which makes it a bit more complicated.

You can use @brucebat's suggestion too, but given the fact that widgets can appear on any page, and in different locations, you'll have to repeat a lot of code, which goes against DRY.