Scrum Primer - Sprints

Sprints are kind of like the heartbeat of Scrum. It's the methodology itself.
Each Sprint has four phases, just like most software development cycles that have been around - Plan, Build, Measure & Learn. Sprints can last anywhere between two to four weeks.

Plan - Plan based on gathered requirements for the Product to be built.
Build - Develop the requirements.
Measure - Testing what has been developed
Learn - Learnings from Testing and alterations to the Plan
...and repeat
All initiatives/projects are executed over multiple sprints, so these four phases repeat themselves. The Learning phase improves the Planning phase for subsequent sprints.
Sprint Events

Sprint Planning (see here)
Planning for each Sprint. Typically owned by the Product Owner.
Daily Scrum (see here)
These are the Daily Stand-Up that occurs as long as the Sprint is in session.
Sprint Review (see here)
Review the Sprints outcome (Increment) with relevant stakeholders
Sprint Retrospective (see here)
Learning from the team about what worked, didn't work and what can be improved before the next Sprint.
Product Backlog Refinement (see here)
Not an official event in a sprint, but done as good practice to improve the Product Backlog. It's where additions, deletions or updates happen to Items (requirements) on the backlog. The Sprint Review usually triggers these changes.
Sprint Inputs and Outputs
