Using SmartGenealogy, from http://alainlecomte.free.fr/Download.htm#SmartGenealogy. You will need to set your spreadsheet up first, but it does get you from Excel to SmartGenealogy and thence from there exported to Gedcom in easy non technical steps.
The best way to do this is:
1. Import an existing Gedcom into SmartGenealogy
2. Export it to Excel
3. Adapt your new data into the format of the Excel sheet you have created
4. Import your new data into a new SmartGenealogy database
5. Finally, export to Gedcom