My colleague Dimitri will be glad to hear I started experimenting with APEX again. I have been doing my home accounting in Excel for years, and it seemed like a nice project to try and build in APEX. As I wanted the data structure to be a little different, I didn't just import the excel sheets, but designed a new data model and started from there. I might still import the excels to have the old data available in Oracle as well, even write a small ETL routine to convert to the new model. For now I'm just having fun learning a new way to make client interfaces.
One of the (mainly SQL) 'issues' I had was creating a select list with all the months of a year, in a meaningful and efficient way. I used a combination of date formatting and a row generator, you can read more about that here.