Mashups allow you to quickly extend TargetProcess UI with almost any functionality you want. There are several places on each page where you can add some new UI, or you can modify the existing UI.
This repository contains some example Mashups both for immediate use and as starting points for developing your own Mashups.
UserStory Templates
Provides a means to pre-populate the description field when adding new UserStories with template data. (Download)
Numeric Rank Display
Replaces the progress-bar style display of Ranks with a numeric text representation of a User Story/Bug/Feature's rank. (Download)
Kanban Board Impending Doom
Colors cards on the Kanban board according to the value of a Date pulled from a Custom Field. To use, add a Custom Field called 'Due Date' of type 'Date' to your Process. The Mashup colors cards Green, Yellow, and Red depending on the amount of time remaining for the card. (Download)