First, we need to start with a default VCL application in Delphi. Because I do not know the ways that Lazarus handles threads I make no promises that it carries over.

Logging and graphing data from temperature (and humidity) sensors. Comes with sourcecode. Tutorial also covers fetching XML from a webserver, as it was written in connection with the Poseidon SNMP / XML LAN / internet "thermometer" (from HW group), but it can be revised to read from other sensors.

To send message from one PC to another.

This tutorial tells you about a freeware DLL for sending messages to and from your PC via the parallel or serial port. The tutorial includes help on how to use it. You could drive electronics of your own devising attached to your PC.

The beginnings of a program to generate online photo albums.

How to draw in the color of your choice. How to make things on your form change size if the window's size is changed.

Not complex, but presented assuming some fluency on part of pupil. Replaces a file with a modified version of itself. Backs up original file.

Display .bmp images on your form. Access all the files in a given folder on your disc, using that as the basis for a "Can you recognize..." exercise. Tutorial has rough edges, but full source listing of working program given.

MoveTo(100,10);DrawTo(300,300); seems simple enough... but it isn't enough to make a line which will still be there after you minimize then restore the window. This tells you how to create persistent graphics, and talks briefly of loading bitmaps.

This tutorial shows you how to send text to a printer a line at a time. There are no complex concepts, but the need isn't universal, and the help is minimal.