A conversation at noon

Tenses and aspect are among the most difficult things to learn in any language, so I've made a pretty chart to simplify the whole thing. It includes an example of a conversation that includes each form at least once.

Click to enlarge!

UPDATE:
It helps if you look at which time phrases you can use with each form (left side of the chart). For example:

The race started at 10am. [the simple past]
The race has started now. [has is present tense, so it is about the past of the present (i.e., a time before now)]
The race had started at 11am. [had is past tense, so it is about the past of the past (i.e., a time before 11am)]

If it is now 12pm, you can't say:

WRONG: The race has started at 10am. [has is present tense, but 10am is in the past, so it doesn't make sense]

If you want to attach a time phrase to start instead of have, use the simple past form.