Bulk Edit Calendar Events
This is the most popular program I have written in my personal time. It uses the full, official Google Calendar API and a GUI to edit Google Calendar events in bulk. It is a C#, Windows desktop application written in the WinForms framework.
The program boasts over 3000 unique users!
Bulk Edit Calendar Events (either the original version or the current version) has been featured in a few prominent websites:
Cedarville University News: https://www.cedarville.edu/News/2015/Student-Creates-Google-Calender-Lifehack.aspx
Bulk Edit Calendar Events has a vast number of features and I’m always taking new suggestions! Here is a brief overview of some of the currently existing features.
Event searching (by query, start date, end date, and number of events)
Event filtering (by title, description, location, and time range)
Title (either by replace all, append beginning/end, or replace pattern)
Location (either by replace all, append beginning/end, or replace pattern)
Description (either by replace all, append beginning/end, or replace pattern)
Copy or Move to another calendar
Move event start time
Visibility (i.e. public/private/etc)
Free/Busy information (also known as “Show me as…”)
Bulk event creating
Ability to import from an already existing event
Ability to create based on a rule (e.g. “every 31st” or “every march”)
Ability to create based on a model week (lets you set up an example week, Sun-Sat, then apply that week to multiple weeks)
Logging and extensive error-catching for debugging any issues that may arise